The Atlanta-based company, one of the nation’s three key credit bureaus that track individuals’ credit histories, said late Wednesday that hackers breached a vulnerable spot in a U.S. website application called Apache Struts CVE-2017-5638. Equifax disclosed last week that it discovered in July that hackers had tapped a large trove of personal data on most adults in America.

But in a statement Thursday, Apache Software Foundation, which provides the application, said it provided and announced a patch for the software fault on March 7, well before Equifax said the security breach began in mid-May.

“In conclusion, the Equifax data compromise was due to their failure to install the security updates provided in a timely manner,” the foundation said.